The inherent porous nature and facile tunability of metal-organic frameworks (MOFs) make them ideal candidates for use in multiple fields. MOF hybrid materials are derived from existing MOFs hybridized with other materials or small molecules using a variety of techniques. This led to superior performance of the new materials by combining the advantages of MOF components and others. In this review, we discuss several hybridization methods for the preparation of various MOF hybrids with representative examples from the literature. These methods include covalent modifications, noncovalent modifications, and using MOFs as templates or precursors. We also review the applications of the MOF hybrids in the fields of catalysis, drug delivery, gas storage and separation, energy storage, sensing, and others. Crystals 2018, 8, 325 2 of 23to coordinate to other materials. In addition to covalent modifications, MOF hybrids can also be made via noncovalent interactions, such as encapsulation [19,20], layer-by-layer deposition [21], and in situ growth [22]. These methods take advantage of noncovalent interactions between MOFs and the hybridizing species by trapping the species within the MOF pores, layering them on top of the parent MOF, or growing MOFs crystals in situ with the species. Noncovalent modification allows the individual characteristics of the MOF and hybridizing materials to work synergistically in the resultant MOF hybrids while requiring less synthetic efforts than covalent modifications. These methods can be used to achieve materials with MOF coating/protection, multi-layered membranes, and the controlled growth of MOF structures with superior performance than individual parent materials. Finally, hybridizing MOFs through use as either sacrificial templates [23] or precursors [24] utilizes the ordered structure of MOFs to afford porous materials with high surface areas and uniform pore sizes. This method eliminates the metal node and/or the organic linker, leaving behind only the newly synthesized materials with the inherited uniform nanoframe of the template/precursor MOF.In this review, we discuss each hybridization method with representative MOF hybrids from literature, as well as the hybrid materials' superior performances and applications. At the end of this review, we also summarize all reported MOF hybrid materials. Crystals 2018, 8, x FOR PEER REVIEW 2 of 22

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We investigated the chemistry of singlet oxygen with a cadmium–sulfur cluster, (Me4N)2[Cd4(SPh)10]. This cluster was used as a model for cadmium–sulfur nanoparticles. Such nanoparticles are often used in conjunction with photosensitizers (for singlet oxygen generation or dye-sensitized solar cells), and hence, it is important to determine if cadmium–sulfur moieties physically quench and/or chemically react with singlet oxygen. We found that (Me4N)2[Cd4(SPh)10] is indeed a very strong quencher of singlet oxygen with total rate constants for 1O2 removal of (5.8 ± 1.3) × 108 M–1 s–1 in acetonitrile and (1.2 ± 0.5) × 108 M–1 s–1 in CD3OD. Physical quenching predominates, but chemical reaction leading to decomposition of the cluster and formation of sulfinate is also significant, with a rate constant of (4.1 ± 0.6) × 106 M–1 s–1 in methanol. Commercially available cadmium–sulfur quantum dots (“lumidots”) show similar singlet oxygen quenching rate constants, based on the molar concentration of the quantum dots.

Systematic X-ray diffraction, transmission electron microscopy (TEM), Raman and magnetic measurements were performed to study the structural and magnetic properties of copper nanoparticles (NPs) in carbon matrix. The weight concentration of Cu in carbon matrix is 8 wt%. The carbon-coated core-shell structures with bimodal size distribution with 4 and 300 nm average sizes of NPs are confirmed by scanning electron microscopy and TEM. Our results on magnetization carried out by vibrational magnetometer for copper NPs provide a strong evidence for coexistence of ferromagnetism and giant paramagnetism in wide range of temperature and magnetic field. The magnetic susceptibility at T = 10 K shows high value of giant paramagnetism with χ = 5×10 −5 emu/g Cu Oe while ferromagnetic behavior with hysteresis is preserved up to the room temperature.